[Bug] Claude Code CLI: Model claude-3-5-fable not available or unsupported

Bug Description
max5x인데 claude code cli에서 fable5.1을 사용할 수가 없음(사용량도 20%) 빨리 조치바람

Environment Info

• Platform: win32
• Terminal: vscode
• Version: 2.1.270
• Feedback ID: a0ca012e-674f-4fba-aa5f-7bef23b11933

Errors

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AND

Title: Fable 5.1 prompts "now uses usage credits" on Max 5x plan despite Fable weekly usage at 15%

Description

On a Max 5x plan, Claude Code shows "Fable 5.1 now uses usage credits — You don't have usage credits yet" and offers only "Switch to Opus 5" or "Buy usage credits". No request reaches the API (session usage stays 0).

Expected

Per the Help Center, Fable 5.1 is included on Max plans up to 50% of weekly usage. It should run without a credits prompt.

Environment

• Claude Code 2.1.270 (native install), Windows, VS Code extension 2.1.270
• Login: Claude Max account, organizationRateLimitTier: default_claude_max_5x
• Usage credits: off (hasExtraUsageEnabled: false)

Evidence

• /usage: Current week (Fable) 15% used, Current week (all models) 8% used
• Fable 5.1 works normally on claude.ai web with the same account
• /status shows Model: claude-fable-5-1, but sending any message triggers the credits dialog

Already tried (no change)

• claude --model claude-fable-5-1 (standard), claude-fable-5-1[1m], and the "fable" alias
• /logout and re-login
• claude update
• Removed additionalModelOptionsCache / cachedGrowthBookFeatures from ~/.claude.json

Notes

• ~/.claude.json additionalModelOptionsCache lists only claude-fable-5-1[1m]
• Same symptom as #79412 / #79337